Masking in humans: the problem and some attempts to solve it.

Different types of masking are discussed together with an account of the masking effect that the sleep-wake cycle exerts upon the circadian rhythms of body temperature and urinary excretion. The relative importance to masking of the several components of differences between sleeping and wakefulness are then assessed. Means to deal with the problem of masking fall into two major categories. These attempt to minimise masking effects by protocols such as constant routines or control days, and mathematical models which separate results obtained in the presence of masking influences into endogenous and exogenous components. (The problem of the extent to which masking influences can render the endogenous component of a rhythm an impure reflection of the internal oscillator is considered also.) These different techniques are compared with respect to their usefulness and assumptions. Finally, a brief speculation is given of the usefulness of masking.

[1]  T. Åkerstedt Altered sleep/wake patterns and circadian rhythms. Laboratory and field studies of sympathoadrenomedullary and related variables. , 1979, Acta physiologica Scandinavica. Supplementum.

[2]  J. Waterhouse,et al.  Circadian rhythms of urinary excretion: the relationship between the amount excreted and the circadian changes. , 1982, The Journal of physiology.

[3]  J. Aschoff,et al.  Exogenous and endogenous components in circadian rhythms. , 1960, Cold Spring Harbor symposia on quantitative biology.

[4]  M. Koopman,et al.  Circadian rhythms and the kidney. A review. , 1985, The Netherlands journal of medicine.

[5]  R Moog,et al.  Optimization of shift work: physiological contributions. , 1987, Ergonomics.

[6]  Karl E. Klein,et al.  Significance of Circadian Rhythms in Aerospace Operations , 1980 .

[7]  J. Waterhouse,et al.  The physiological rhythms of subjects living on a day of abnormal length. , 1977, The Journal of physiology.

[8]  J. Waterhouse,et al.  The effect of sleep upon human circadian rhythms. , 1978, Chronobiologia.

[9]  Jürgen Aschoff,et al.  The Circadian System of Man , 1979 .

[10]  J. Davies,et al.  Circadian Rhythms in the Central Nervous System , 1985, Satellite Symposia of the IUPHAR 9th International Congress of Pharmacology.

[11]  D. Minors,et al.  Effects upon Circadian Rhythmicity of an Alteration to the Sleep-Wake Cycle: Problems of Assessment Resulting from Measurement in the Presence of Sleep and Analysis in Terms of a Single Shifted Component , 1988, Journal of biological rhythms.

[12]  J. N. Mills,et al.  Human circadian rhythms. , 1966, Physiological reviews.

[13]  J. Waterhouse,et al.  Adaptation to abrupt time shifts of the oscillator(s) controlling human circadian rhythms. , 1978, The Journal of physiology.

[14]  S. Lightman,et al.  Circadian rhythms of epinephrine and norepinephrine in man. , 1985, The Journal of clinical endocrinology and metabolism.

[15]  David Minors,et al.  Circadian Rhythms and the Human , 1981 .

[16]  F. Halberg,et al.  Circadian characteristics of urinary epinephrine and norepinephrine from healthy young women in Japan and U.S.A. , 1986, Chronobiology international.

[17]  A. Muzet,et al.  Ultradian oscillations in plasma renin activity: their relationships to meals and sleep stages. , 1985, Journal of Clinical Endocrinology and Metabolism.

[18]  J. Waterhouse,et al.  Mathematical and statistical analysis of circadian rhythms , 1988, Psychoneuroendocrinology.

[19]  J. Aschoff,et al.  Thermal Conductance in Man: Its Dependence on Time of Day and on Ambient Temperature , 1972 .

[20]  J. Hershman,et al.  Effect of 64-hour sleep deprivation on the circadian waveform of thyrotropin (TSH): further evidence of sleep-related inhibition of TSH release. , 1987, The Journal of clinical endocrinology and metabolism.

[21]  P. Mullen Sleep and its Interaction with Endocrine Rhythms , 1983, British Journal of Psychiatry.

[22]  J. Waterhouse,et al.  The circadian variations of the rates of excretion of urinary electrolytes and of deep body temperature. , 1976, International journal of chronobiology.

[23]  A. Borbély A two process model of sleep regulation. , 1982, Human neurobiology.

[24]  J Aschoff,et al.  Features of circadian rhythms relevant for the design of shift schedules. , 1978, Ergonomics.

[25]  M. Moore-Ede,et al.  Physiology of the circadian timing system: predictive versus reactive homeostasis. , 1986, The American journal of physiology.

[26]  J. C. Zimmerman,et al.  Cortisol secretion is inhibited during sleep in normal man. , 1983, The Journal of clinical endocrinology and metabolism.

[27]  David Minors,et al.  The role of naps in alleviating sleepiness during an irregular sleep-wake schedule , 1987 .

[28]  J. Waterhouse,et al.  The use of constant routines in unmasking the endogenous component of human circadian rhythms. , 1984, Chronobiology international.

[29]  A. R. Scott,et al.  CIRCADIAN RHYTHMS, INTERCONTINENTAL TRAVEL AND SHIFTWORK , 1987 .

[30]  T Reilly,et al.  Investigation of circadian rhythms in metabolic responses to exercise. , 1982, Ergonomics.

[31]  J. Waterhouse,et al.  Does ‘anchor sleep’ entrain circadian rhythms? Evidence from constant routine studies. , 1983, The Journal of physiology.